Now an inseparable pair, that wasn’t always the case. From the moment these two mismatched monsters met they couldn’t stand each other. Monsters University unlocks the door to how Mike and Sulley overcame their differences and became the best of friends.

“We get to show off their differences,” producer Kori Rae told EW. “They both approach life in different ways. Mike is the go-getter type, anything is possible, and he’s the super-hard worker. Sulley is different because he’s a great scarer, he has this natural ability, but Mike has to work for it.”